Process of treating photographic layers in a bath containing a wetting agent and new preparations intended for acting on photographic layers



Patented May 7, 1935 PROCESS OF TREATING PHOTOGRAPHIC LAYERS IN A BATH CONTAINING A WET- TING AGENT AND NEW PREPARATIONS INTENDED FOR ACTING ON PHOTO- GBAPIIIC LAYERS Albert Schaefl'er, Marxlieim in Taunua, Germany,

aasignor to Agfa Anaco Corporation, Binghamton, N. Y., a corporation of New York No Drawing. Application January 5, 1931, Serial No. 506,838. In Germany January 13, 1930 a 8 Claims.

The present invention relates to a process of treating photographic layers in a bath containing a wetting agent and to new preparations intended for acting on photographic layers, the photographic layers being such as contain a silverhalide emulsion.

It is known .that in developing photographic materials, such as plates, films'and papers, undesired bright spots often occur on the layer side of the material (of. Agfa-Photobliitter 1929, page 125). These spots are generally caused by air bubbles which adhere to the layer when the plate, film or paper is brought into the developer and prevent the developer from acting upon the silver bromide covered by the bubbles, and this unattacked silver bromide subsequently dissolves in the fixing bath. Hitherto, this drawback could be avoided only by stroking over the layer side of the photographic material with a piece of wadding directly after the plate or the like was brought into the developer and before any trace of the picture was to be seen. By this inconvenient operation the air bubbles were removed, but often the layer was entirely spoiled by scratchmg.

According to this invention the formation of air bubbles and the consequent undesired spots are entirely avoided by introducing the photographic material such, for instance, as the plate, film, paper or the like, before developing it, into a bath containing a small quantity of an organic wetting agent, such as, for instance, pyridine, mcnopol soap i. e. castor oil sulfonic acid, an aromatic sulphonic acid which is alkylated or aralkylated in the nucleus or a salt thereof, or the like. With the same result the wetting agent may be added directly to the developing bath or to another photographic bath, such, for instance, as a desensitizing bath.

The following examples serve to illustrate the invention, but they are not intended to limit it thereto:

(1) 2 grams of para-aminophenol are dissolved in 100 cc. of water. 6 grams of dry sodium sulphite, 12 grams of potassium carbonate, 0.3 gram of sodium dibutyl-naphthalene-a-sulphonate are dissolved in 200 cc. of water. The solutions are mixedtogether and the plate, film or the like is developed in the mixture as usual at about 18 C.

(2) 300 cc. of a solution of a commercial desensitizing agent are mixed with 1 cc. of pyridine. The plate, film or the like is placed in the solution for.2 minutes in a dark red light and then developed in an orange colored light in one of the 5 usual developers.

(3) 0.5 gram oi monopol soap is added to 300 cc. of water. The exposed plate, film or the like is wetted in the liquid for -l minute and then developed in one of the usual developers.

(4) 1 gram of hydroxy-phenyl-glycine is dissolved in cc. of water which contains 5 grams of crystallized sodium sulfite. 5 grams of potassium carbonate and 0.2 gram of sodium benzylnaphthalene-sulfonate are added to the solution. The film, plate or the like is developed in this solution in the usual manner.

(5) A developer is prepared from 50 grams of cystallized sodium sulfite, 10 grams of glycine, 50 grams of potassium carbonate, 3 grams of sodium dibutylnaphthalene-a-sulfonate and 200 cc. of water. This developer is to be diluted with 4-5 times its weight of water and the exposed plate, film or the like is developed therein in the usual mannen In the following claims, the term alkylated aromatic compound is intended to include likewise the corresponding aralkylated compounds.

I claim:

1. Photographic developers for silver-halide emulsions containing sodium benzylnaphthalene sulfonate.

2. Photographic developers for silver-halide emulsions containing a sulfonic acid of an alkylated aromatic hydrocarbon.

3. Photographic developers for silver-halide emulsions containing an alkali metal salt of a sulfonic acid of an alkylated aromatic hydrocarbon.

4. Photographic developers for silver-halide emulsions containing sodium dibutyl-naphthalene-a-sulfonate.

5. In the process of preparing pictures from photographic silver-halide preparations the modification which consists in efifecting the developing process in the presence of a sulfonic acid of an alkylated aromatic compound.

6. In the process of preparing pictures from photographic silver-halide preparations the modification which consists in eflecting the developing process in the presence of an alkali metal salt of a suitonic acid or an alkylated aromatic 5 compound.

7. In the process of preparing pictures from photographic silver-halide preparations the modification which consists in eflecting the developing process in the presence 01 sodium dibutyl-naphthalene-a-sultonate.

8. In the process of preparing pictures from photographic silver-halide preparations the modification which consists in effecting the developing process in the presence of sodium benzylnaphthalene sulfonate.

ALBERT SCHAEFFER. 

